So, if I want to sprint off a cliff, I can't? Or do you have to pull the stick back to make that animation? If so, can you do it not at the cliff's edge? Can I sprint anywhere and pull back to stop and trigger that animation? That's possible. It's also possible that it was just a cutscene. Who knows?
Let's not forget that Bethesda (as much as I love it) is not above exaggerating some features. Until I hear otherwise, I'll assume it was just part of a cutscene. I prefer to err on the side of caution.
Ultimately this is the stance that makes the most sense. In all seriousness guys, that could have been any number of things.
Cutscene? -Possibly, gamesas has done that before.
Cliff response of some kind? -Sure why not, could be a perk of some kind.
Reaction to running and halting? -Very likely
Reaction to running, and stopping, and the cliff? -Could be.
There's really no way to know. My
sense is that it is #3, but that's just because it seems to make the most sense to me, personally.